Because a typical trailer hitch couples a trailer to a towing vehicle at a spot behind the rear axle of the towing vehicle, any substantial (or even slight) lateral movement of the forward end of the towed trailer can result in simultaneous lateral shifting of the forward end of the towing vehicle. Lateral movement in the trailer that is not induced by the operator of the towing vehicle can be exceedingly dangerous. Such lateral movement might be caused by, for example, the impact of a strong crosswind on a trailer having a large side cross-sectional area. Similar dangerous movements may be caused by a slipstream impact from a large passing vehicle. These effects can be exacerbated if the trailer is not properly loaded, such as when the center of gravity of a trailer load is disposed forward of the wheels of the trailer and a substantial proportion of its mass rests on the hitch.
Trailer hitches having no anti-sway function provide no resistance to lateral loads induced by trailer movement. Trailer hitches having an anti-sway function provide some resistance to lateral loads, but known hitches do not have the capability to actively correct sway. Known devices also are not capable of automatically releasing anti-sway corrective forces when they are no longer needed, such as when a user maneuvers a towing vehicle and a trailer in tight spaces and lateral movements of the trailer are desired.